Apparatus for punching and working metal



1943- A. M. BROWN 2,308,953

- APPARATUS FOR ruucnme AND WORKING METAL Filed Sept. 15,1959 s Sheets-Sheet 1 INVENTOR BY fi al K ATTORN EYS 1943 A. M. BROWN 2,308,953

APPARATUS FOR PUNCHING AND WORKING METAL Filed Sept. 13, 1939 3 Sheets-Sheet 2 INVENT6R ATTORN EYS 4 A; M. BROWN I 2,308,953

APPARATUS FOR' PUNCHING AND WORKING METAL Filed Sept. 15, 1939 3 Sheets-Sheet 3' mvzu'rda I I 5 JZie/uZaZd/Zfimm J BY 7 f E 7 Q "3? I ATTORNEY Patented Jan. 19, 1943:

2308,9 1 A, APPARATUS FOR PUNCHING won nNG MlITAL Archibald Brown, Trenton, Mich., assignorto' TheFirestoneTire & Rubber Company, Akron,

v Ohio, a corp ration of Ohio Application September 13, 1939, Serial No. 294,662

' ZCIaims. (01.113-42) This invention relatesto punching and-working metal, more especially to punching 'or trimrning metal'jhaving ahole therethrough'to enlarge the 7 size of the hole, and thereafter drawing the portion of the metal adjacent the hole to form tuberance on the metal.

Heretofore standard practice in punching holes through 'sheetmetal has been toprovidea' I clearancebetween-the punch and the die of approximately 10% of the thickness of the metal. When punching thinmetals,'.'for example of .02 inch thickness, this permits aclearance of only .001 inch on" each sideof the punch as it enters a pro the. die,* Thus.any slightwibration of the machine will cause the punch to hit the side of{ the die and :spoilthe hole produced in the sheet metal. Also, any roughness in the edges of the punched-hole, especially in stainless steel, pro-3 duces splits in the metal, if it subsequently is drawn or otherwise worked to form an outwardly extending boss or other member on the sheet metal. -Usually after a holeis' punched in a piece of' sheet metal, the hole is made clean and smooth by-buffing orreamingsame, and then" the metal adjacent the hole is drawn to the desired shape.'

One general object of this invention" is to pro-J.

vide an improved, uncomplicated l method ,of, forming a smooth hole through metal, and to I provide sturdy, inexpensive machinery for practicing the method. g p Another object of the invention is to simplify and reduce the cost of punching a hole ini'a sheet metal member and thereafter in the same operation, drawing the metal adjacentthe hole.

outwardly therefrom to form an integral boss on the sheet metal member,

Other objects of the invention will be manifest from the following specification, which will be described with particular reference to the accompanying drawings, in which:

Figure 1 is a vertical'cross sectional view of apparatus embodying the invention at the starting point of its operation;

Figure 2 is a similar view. of the apparatus of Figure 1 with the punch in engagement with I the die;

Figure 3 is a view of the apparatus of Figure l in its final position with the upper member in engagement with the die; and

Figure 4 is a section through the integral bung formed on a sheet metal member by practice of the invention. 7

Broadly speaking, the present invention comthan the desired size in a piece 'of sheet metal and'partially drawing, or pressing out thefmetal thereadjacent, and thereafter trimming the aperture to the desired size by avpunch having fa,

centeringmember associated therewith. 'Initial movement of the punch engages the centering member with a bushing carried in a hollowdieto center the punch with relation to the die; after which the centered punch, on continued -move-' ment thereof, engages with the die andtrims the Asjthe member carrying the punch and centering member continues to move toward the hollow die, 1 it draws orfpressesoutfthe metal adjacent the, trimmed aperture by engagingwiththe outside; of'fthe die, j i I The present invention will be described par- 7' ticularly 'withreference tothe provision of an integral boss on a stainless steel. sheet metal,

.meniber such'as is used inthe construction of,

beverage containers, although it will be apparent" that the, invention may be used merely to form a smooth, polishedhole through any desired metal the recess ll,

prises the steps of forming an aperture of less 55 member, or'that other types of drawn metal protuberances on apertured metallic objects may be formed by practice of the'inventio a Referring specifically to the apparatus shown in Figure 1, it-inc ludes a suitably mounted base a plate ill whichhas' a'centralrecess H and a pluralit'y of smaller recesses 12 formed therein, the small recesses l2 being formed in a circle around the recess H or in parallel rows on both sides of snugly received in the recess I mounteduponthe base, plate l0. The hollow die 13 has a bore [4 which has a reduced diameter adjacent the upper end thereof, with a centering bushing 15 being receivedin the bore 14. This bushing l5, having a bore l6, has a small flange ll formed thereon adjacent its base, which flange engages with a shoulder l8 formed in the centering bushing at the reduced diameter thereof.

I and thereby Normally the centering bushing I5 is held in engagement with the shoulder I I8 by a spring l9 wh ch also is within the centering die I5 and which bears upon the base plate l0. In orderto mount a sheet metal member 2| upon the hollow die l3, a supporting plate 22 is carried by the base plate I 0 by a plurality of springs 23 WhlCh engage with the recesses I! of the base plate and with corresponding recesses 24 formed in the supporting plate. Before positioning the sheet metal member 2| on the supporting plate 22, it will be observed that a hole formed therein and that the portion 26 of the aperture inthefsheet'metafto the desiredsize. 5

as desired. A hollow die I3 is 25 has been sheet 'metal member thereadjacent has been drawn or pressed out slightly from the plane the remainder of the member.

The punching apparatus of the-invention comprises a cylindrical punch 21 which is mounted in an upper member 28 that is movable relative to the base plate l0 and the apparatus carried thereon. The upper member 28 has a cylindrical recess 29 formed therein immediately adjacent the cylindrical punch 21, which is received with:

in the periphery of the upper member. The punch 21 is centered relative to the hollow die l3 by a centering finger 3| which is carried by the on metallic members is facilitated and the obpunch and which extends downwardly from the a center of the punch. The centering finger 3| has a tapered end portion 32 which is adapted to engage with the centering bushing l5 when the upper member is moved downwardly relative to the base plate and center the punch 21 relative to the hollow die I3. In engaging with the centering bushing, the centering finger extends through the hole 25 formed in the sheet metal member 2] Thus upon downward movement of the upper member relative to the base plate, the centering finger first engages with the centering bushing and then the cylindrical punch shears off, or trims the metal adjacent the hole 25 due to the punch passing within the hollow die l3. In passing into the hollow die, obviously the centering punch 21 depresses the spring 19 and the centering bushing l5 (Figure 2).

Continued downward movement of the upper member acts to engage the cylindrical recess 29 with the outer portion of the hollow die l3. In doing this, the upper member 28 further draws out the pressed 'out portion 26 of the sheet metal member 2! until it is perpendicular to the remainder of the sheet metal member, as shown in Figure 3. The outer portion ofthe end of the hollow die I3 is rounded oif as at 33 to facilitate the initial drawing or bending of the sheet metal member due to engagement with the upper mem;

her while it is carried on the hollow die l3. As shown in Figure 3, downward movement of the upper member 28 depresses the supporting plate 22 in order that the cylindrical recess 29 may be forced downwardly over the hollow die l3 the desired distance.

'Figure 2 best illustrates that" an annular ring 34 is sheared or trimmed from 'the sheet metal member 2| at the first portion of the downward stroke of the upper member. Due to the centering finger engaging with the centering bushing, only a very small clearance between the punch 21 and the die 13 need'be provided. This insures a hole of the desired size being formed in the sheetmetal member and the exact fitting of the punch and die aid in forming a smooth, clean hole inthe metal sheet 2|. Formation of the J'ects of the invention are achieved.

While one embodiment of the invention has I been completely illustrated and described herein,

it will be understood that various modifications thereof may be made without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. Apparatus for forming protuberances in metallic members comprising a base plate, an apertured supporting plate, springs mounting said supporting plate on said base plate, a hollow die carried by said base plate and extending through said apertured supporting plate, a centering bushing slidingly received in said hollow die, a spring supporting said centering bushing on said base plate, anupper member having a recess therein adapted to be moved down around said hollow die, a punch carried by said upper member to engage withsaid hollow die and shear ofi any material thereon, and'a centering finger carried by and extending downwardly from said punch to engage with said centering bushing and center said punchrelative to said hollow die prior toengagement thereof.

2. Apparatus for forming protuberances on metallic members comprising a base plate, an apertured supporting plate carried on said base plate, a hollow die carried by said base plate and extending through said apertured supporting plate, a centering bushing slidingly received in said hollow die, an upper membena punch carried by said upper member to engage with'said hollow die and shear off any material thereon,

i said upper member having a recess formed therein around said punch to form a chamber adapted to receive said die therein, said die being adapted to force any material thereon against the portion of said upper member defining said recess and draw out such material to form a protuberance thereon, and a centering finger carried by and extending downwardly from said punch to engage with said centering bushing and center said'punch relative to said hollow die prior to engagement thereof.

ARCHIBALD M. BROWN. 

